1. Field of the Invention
This invention relates generally to the field of automatic screw-feed machines and in particular to methods and apparatus for utilizing a plurality of screw-feed machines to feed a single outlet.
2. Description of the Prior Art
In general, automatic screw-feed machines serve the function of delivering a single screw, rivet, pin, or other like fastener to a work site which is remote from a container having a plurality of such fasteners contained therewithin. Automatic screw-feed machines are used in manufacturing where a large number of fasteners are to be applied to the products being assembled or joined. They are mass-production devices which avoid having a worker hand select a fastener from a container and then apply the fastener to the work.
In accordance with the above, a typical prior art automatic screw feed machine comprises a storage container which usually rotates to feed fasteners in a preferred orientation relative to a track arrangement. The track arrangement delivers the aligned fasteners to an escape mechanism which further orients a single fastener and feeds the fastener into a tube. Air power is then used to drive the fastener along the length of the tube to an outlet. An air-operated tool such as a screw driver or riveting machine might be connected to the outlet so that the worker can position the fastener to its assigned location on the work piece and apply the fastener or rivet it in place.
Of course, automatic screw-feed machines must be free of any malfunctions which cause jamming of the fasteners anywhere along their path from the storage bin to the tool at the location where the fastener is to be used. Nasco Ind., Inc. by and through its employees has invented and patented a number of improvements to automatic screw-feed machines which have, over the years, demonstrated their effectiveness in preventing malfunctions, speed up production, and substantially benefit the worker by improved ergonomics. U.S. Pat. No. 4,671,143, "Driver Jaws for an Automatic Screw Feeding Machine," is one such invention which utilizes cantilever springs to hold and position a fastener during assembly. U.S. Pat. No. 4,694,974, "Escapement Apparatus for an Automatic Screw Feeding Machine," is another invention of Nasco Ind., Inc. which smoothly removes a single fastener from a track, orients it, and then inserts the fastener into the tube which leads to the driver jaws. "Track Feed Arrangement for an Automatic Screw Feeding Machine," U.S. Pat. No. 4,732,296 is yet another invention of Nasco which provides for efficient and non-malfunctioning of the movement of fasteners from a storage bin to an escapement mechanism. An even further contribution of Nasco is disclosed in U.S. Pat. No. 5,234,127, "Pneumatic Automatic Fastener Feeder." In this invention, up-and-down pivoting motion of the track provides for removing fasteners from the storage bin and delivering the same to the escapement mechanism. In the trade, this invention is characteristically referred to as a `woodpecker` machine because of the similarity of the up-and-down movement of the track to the head of a woodpecker. A large number of automatic screw-feeding machines are in use today which utilize the inventions of Nasco and serve as a testimonial to the effectiveness of its innovations in the industry.
Aircraft manufacturing facilities use a substantial number of automatic screw-feeding machines to assembly commercial and military aircraft, both large and small. In this industry, the screw-feeding machines deliver rivets to a rivet gun which a worker uses to rivet the metal components forming the wings and body of the aircraft to the underlying support members and/or to fasten wing and body sections to each other. Typically, assembly of a single aircraft involves the use of a large number of different sized rivets. The size differences include both diameter and length depending upon the location where the rivets are to be used on the aircraft. For example, the diameter of the rivets used to fabricate a wing continually change from large rivets used near the body of the plane to smaller and smaller rivets as the tip of the wing is approached. In view of the sheer number of rivets used to assembly an aircraft in conjunction with the different rivet sizes, it is readily understood that a large number of automatic screw-feeding machines are necessary in aircraft construction.
The physical space required to house the large numbers of automatic screw-feeding machines used in aircraft construction presents a formidable problem in and of itself. The space required by the screw-feeding machines take up space around the aircraft during construction. Workers must continually work around the presence of the machines. Clutter is created which leads to inefficiency. The large number of feed tubes from the machines to the worker also create efficiency and clutter problems. The workers must continually change to different feed tubes to be able to apply the properly-sized rivers. A better system would be most advantageous.
Accordingly, a major objective of the present invention is to significantly reduce the clutter around the work space of an aircraft during construction and allow for more efficient fabrication of aircraft wings and bodies.
Another object of the present invention is to provide a manifold for use with a plurality of automatic screw feed machines and to provide a single feed tube to a riveting tool whereby a plurality of different sized rivets or fasteners are capable of being feed from the automatic screw feed machines to the riveting tool at the selection of the operator.